Electric toothbrushes generally impart a brushing action to teeth through oscillatory or rotational motion of one or more parts of a brush head. For example, one known toothbrush comprises a handle and a shaft housing a motor-driven drive mechanism, and a cleaning head having bristles mounted for oscillatory motion by the drive mechanism about an axis transverse to the shaft. Other electric toothbrushes comprise bristles mounted for rotational motion about an axis which is generally parallel to, or co-linear with, the shaft. The bristles may be mounted on a cylindrical brush head for rotation about the longitudinal axis of the head. Alternatively, it is known to mount bristles on a generally spherical brush head which is rotated about the axis of the shaft. For example, WO2008/125269 describes an electric toothbrush in which a spherical brush head is divided into two generally hemispherical sections. The drive mechanism is arranged to rotate the head about a first axis which is co-linear with the longitudinal axis of the shaft, while simultaneously rotating the two hemispherical sections in unison about a second axis orthogonal to the first axis.